Carbureter



j. T. JENNNGS.

CARBURETER.

APPLICATION FILED 00124, 19m.

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Mmmm@ Img., MQ W W., wilnllv wann Lma L T. HNNINGS.

CARBURE'I'ER.

APPLicATmN HLED UCLM. 191s.

4 SHEETS-SHEET 2.

M JM wm L T. JENNENGS.

CARBUHETER.

APPLICATION FILED 0CT.24|1916.

4 SHEETS-SHEET 3.

niet --y/ CAHBURETER, /x-PPLICANON FILED 00124, 1916. MMM? 35m, PatentedAug., 17, 1920an 4 SHEETS-SHIEET 4.

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tl li UNITED STATES 'PATENT OFFICE.

CARBURETER.

Speccationof Letters Patent. Patented Aug. 17, 1920,

Application mea october 24, 191e. serial No. 127,446.

To all fw/tom t may concern:

Fte it known that I, JOHN THOMAS JEN- NINos, subject of the King ofGreat Britain, residing at 35 Wharf road, Kings Norton, Birmingham, inthe county of Warwick, Fingland, have invented a new and usefulCarbureter for Internal- Combustion Engines; and l do hereby declare thefollowing to be a full, clear, and exact description or' the same.

My invention refers to improvements in carbureters for internalcombustion engines.

Various vterms of carbureters have heretotore been proposed in which'the suction at the jet or the size or number of the jet or jets isautomatically varied according to the position of the throttle valve,but 1n such cases the mixtures were approximate to one constant mixtureor infinitely variable, whereas the primary object of the presentinvention is to provide for two or more specilic mixtures eachapproximately constant at varying powers obtained by defined or limitedmovements of the carbureter control.

Further objects of the invention are 1mprovements in the construction of`various parts or carbureters. n

According to this invention I employ in combination means for giving apractically constant mixture at varying powers by the automaticvariation of the area of the air inlet; and means for altering theproportion of fuel delivered; all so arranged that a plurality of specicmixtures each approximately constant at varying powers are obtainable atwill.

Referring to the drawings Figure 1. is a sectional elevation of acarbureter according to'this invention in which two specific mixturesare obtainable by raising and lowering the choke tube.

Fig. 2. is a part sectional view showing the choke tube in its loweredposition.

Fig. 3. is a detail View of the spring and detent for retaininv thechoke tube in one or its extreme positions. l

Figs. 4 and 5. are sectional detail views showing modified forms ofchoke tubes.

Fig. 6 is an enlarged detail sectionalview of a form of the invention inwhich the specie mixtures are obtained by raising and lowering a needlevalve which varies the effective area of the jet.

Fig. 7. is a plan of same.

Fig. 8. is a detail showing means whereby the n umber of jets inoperation may be varied instead of varying the effective size of thejet.

Flg. 9. is a sectional view of another form of carbureter according tothis invention.

F 1g. 10. is a detail section showing the cam actuated means for raisingand lowering the choke tube to change from one specific mixn ture toanother.

Flg. 11. is a.. sectional view showing the spring which returnsthethrottle slide after it has been rotated by the primary lever.

Fig. 12 is an inverted plan view of Fig. 9.

Fig. 13 is a view in section on line X-X of Fig. 10.

Fig. 14 is a sectional perspective view or the form of the carburetorshown in Figs. 9 to 13, showing the plate L11 in one position.

Figa 15 is a detail sectional perspective view of the same, showing theplate 41 in another position.

In automatic carbureters oli the type as illustrated in the drawings inwhich the depression at the jet is practically constant for any givenpower, but not at all powers, and 1s affected normally only by variationin depression in the mixing chamber, l may use a sliding choke tubehaving a tapered bore by the movement of which different diameters ofits bore may be brought opposite the jet orifice, giving differentdepressions for any particular rate of flow through the choke tube.Byproviding that the choke tube may have a relatively free or a variously restricted outlet at will the same re sults can be obtained. Thesemethods of'obtaining various mixtures are possible when a portion onlyof theair su ply is admitted through the choke tube. 'he relationbetween the strong and the weak mixtures is not constant at all powersby this latter method but in some ways this may be an advantage.

In carrying my invention into practice illustrated in the accompanyingdrawings 1n Figs. 1 3 applied to a carbureter of the type where thedepression at the jet is approxi- -mately constant at any given power,the

throttle slide 1 controlled by Bowden wire mechanism 2, against theaction of a spring 3, is provided with an upper abutment 4 and a lowerabutment 5, the upper abutment 4 serving to lift the choke tube 6 bymeans of (ill the rod 7 and sleeve 8 when the said throttle is raised toits highest position, the abutment 5 being adapted to engage with theabutment 9 connected to the choke tube when the throttle is in itslowest position and serving to depress the choke tube to the positionshown in Fig. 2. Thus the whole of the movement of the Bowden Wiremechanism is employed solely to move the throttle slide with theexception of the extreme outward movements of the lever at the ends ofits stroke which serve to either raise or lower the choke tube. Thepower is thus regulated by a single control and to alter the position ofthe choke tube and to obtain the second of the specific mixturesobtainable, the control is moved over its extreme position when eitherthe abutment 4 strikes the sleeve 8 and thus lifts the choke tube or theabutment 5 engages the top of the choke tube and lowers it so as to givethe second of the specific mixtures obtainable.

As illustrated the carbureter is provided with air valves 10 while agauze l1 is provided for covering the admission to the air inlet ports12 and 1() such valves beine' of such weight or being suitably weightedIby springs, so as to give a practically constant mixture at all speeds.These valves open by suction and are so loaded that the amount of valveopening is automatically propor tioned to the suction of the engine.

The petrol or the like is fed from the float chamber 13 to the jet 14through the passa e 15.

eans are provided for retaining the choke tube in one of its twopositions against involuntary movement, such means including the Springmember 16 provided with a detent 17, the spring being mounted upon therod 7 by nuts 18, while the detent 17 engages with a rim 19 upon amember 20 screwing in a fixed part of the carbureter and obviously bypartly rotating the member 20, it lifts the sleeve 8 and prevents thechoke tube 6 from seating itself on the tubular piece 28, the slightopening thus provided giving additional suction at the jets through theports 29 in the choke tube. To retain the member 20 in its adjustedposition itl is provided with a number of notches around its peripherywhich engage with the bifurcated end of the spring 16 and preventinadvertent rotation. By adjusting the nuts 18 and the spring 16 uponthe rod 7 it will be obvious also that adjustment of the movement of thechoke as controlled by the throttle can be obtained. As shown in thedrawings the spring 16 is clamped on the rod 7 between the two nuts 18,18 and the spring is moved when the nuts are adjusted along the rod. Themember 2() gives a finer adjustment by displacing the rim 19 relativelyto the spring.

In Fig. 4 a modified form of choke tube 6 and jet 14 are illustrated,the choke tube having an outwardly expanding and tapered bore while thejet has upwardly inclined orifices 22.

Fig. 5 shows another modified form of choke tube which has an upwardlycontracting tapered part.

In Figs. 4 and 5 there are no side openings in the choke tube such asare shown in Figs. l and 2. The choke tube operates by sliding up anddown and thus bringing an annular space with varying areas opposite thejet orifices. This results in varying air velocities opposite theorifices and consequent varying velocities of efllux of fuel. The choketubes are moved to give the two specific mixtures in the same way as isthe choke tube in Figs. 1, 2, and 3.

In automatic carbureters as shown by Figs. 6, 7 and 8 which normallyhave a fuel orifice of a constant area I may provide for the specificvariations in the mixture bv suitable variations in the area orifice orin the number of them. The restrietion to the fiow of fuel may be at anypoint between the float chamber and the jet extremity.

In Figs. 6 and 7 an arrangement is shown in which the movable choke tubeis dispensed with and means provided in the form of a needle valve 23for adjusting the effective area of the jet which is obtained by raisingor lowering the needle valve to one of two specific and predeterminedpositions. The needle valve is displaced in the same way as the choketube shown by Figs. l, 2, and 3.

Fig. 8 shows a method by which the number of jets in operation may bevaried. When the jet regulator 30 is in its lowered position the orifice31 only is in operation but when the jet regulator is raised ofi theseating 33 the orifice 32 is also in operation, liquid fuel passingaround the outside of the regulator 30 and then through the orifice aswell as through the orifice 31. When the regulator is on its seating itis impossible for fuel to pass the seating and therefore it cannot reachthe orifice 32.

In Figs. 9 to 11 another form of carbureter is shown which comprises abody member 35 containing a rotary throttle valve 36. In this carbureterthe graduation of the range of suction at the jet 37 is effected bylight valves 38 loaded by springs 39 carried in a casing formed byannular plates 40, 41 secured to the carburetei body. The valves areloaded so that the valveopening is automatically proportioned to thesuction of the engine. The plate 41 forms seatings for the valves 38while the plate 40 has projections 42 which act as guides for thesprings 39 thus securing the valves against of the fuel i lateraldisplacement and also acting as stops ulating valve member 44, whichlatter has a series of openings 45 corresponding with the air valveopenings, so that by rotating this member 44 the valve openings may beclosed if required as when starting up the engine. This member 44carries the gage 46 and is held in place by a spring 47 disposed betweenthe member 48 screwing into the tube 43 and the said member 44, so thatthe member 44 is `frictionally retained in any position to which it maybe adjusted.

In top of the tube 43, is an internally tapered choke tube 51 beneathwhich is a spring 52 seeking to lift the choke tube, an adjustable stop53 being disposed above the choke tube for limiting the extent to whichthe choke tube may rise. Also above the choke tube is a bell crank lever54 restin upon the top of the choke tube and thus orming a secondadjustable stop, this bell crank lever being formed from slightlyresilient wlre the second member ofM the lever engaging with theperiphery of a cam 55 so that when this second member of theleverengages the higher point of the cam the choke tube 1s depressed toits lower position, while when the cam is rotated so as to bring thedepression 56 against the bell crank lever, the choke tube then risesunder the influence of the spring 52 to its higher position.

The cam is provided with a slot 57 which engages with a projection 58fixed on the carbureter body and which serves to limit the extent towhich the cam may be rotated. The cam has a second slot 59 which isengaged by a projection 60 which is upon the throttle slide 36, therebeing thus a certain amount of lost movement between the throttle slideand the cam, equal to the length of `this slot so that thecam is notmoved during part of the travel of the slide, but'if the throttle slideis moved to its extreme limit, i. e., beyond a predetermined range ofthrottle opening, the projection GO will then reach the end of the slot59, and then move the cam thus serving to either depress the choke tubeor to permit it to rise.

In operation when the throttle is rotated the projection 60 moves withit in a clockwise direction and the cam 55 remains stationary untiltheprojection 6 0 comes into contact with the end of the slot 59. Uponfurther rotation of thel throttle 36 the cam 55 moves with it. Thismotion can take place until the end of the slot 57 comes into contactwith the stop 58.

When the choke tube is in its lower position there is one specificmixture or specific proportion between f the fuel and air, the

throttle valve operatin to open or close the air without altering thismixture, but an extended movement of the throttle valve serves to changethe position. of the choke tube and thus the proportion between fuel andair thus producing a second specific mixture.

The throttle valve may be conveniently actuated by means of a cable 62secured to the throttle valve at 63 the pull upon the lcable serving torotate the throttle valve which is returned to its normal position bymeans of the coiled spring 64, one extremity of which abuts a ainst thecasing at 65 and the other extremity of which abuts against a part 66 onthe throttle slide, By providing another or intermediate step upon thecam a third. specific mixture may be obtained.

What I claim then is 1. In a carbureter, the combination of a bodymember, means for giving a practically constant mixture at varyingpowers by the automatic variation of the area of the air inlet, a jet, amovable controlling member associated with said jet and adapted tocontrol the passage of fuel therethrough, a throttle valve, an operatingmember for said throttle valve, and means for associating the movementof the throttle valve with the movement of the said movable controllingmember, whereby during the first portion of the opening of the throttlevalve the fuel supply control remains approximately stationary, butduring the latter portion of the throttle opening the fuel supplycontrol is adjusted to increase the fuel supply, so giving two distinctmixtures, a weak mixture succeeding a closure of the throttle and astrong mixture succeeding a full opening of Y the throttle, quiteindependent of the running of the engine.

2. In a carbureter'the combination of a Ibody member, means for giving apractically constant mixture at varying powers by the automaticvariation of the area of the air inlet, a jet, a movable controllingmember associated with said jet and adapted to control the passage offuel therethrough, a throttle valve, an operating member for saidthrottle valve, a member associated with said movable controlling memberand by a lost motion mounting with said throttle valve whereby duringthe 4first portion of the opening movement of the throttle valve thefuel supply control remains approximately stationary, after whichfurther opening of the throttle serves to adjust the fuel supply controlto increase the supply of fuel until this reaches a maximum, after whichthe throttle can be brought back to an approximately closed positionwithout materially albody member; means for giving a practicallyconstant mixture at varying powers by the automatic variationof the areaof the air inlet; a jet; a choke tube disposed around the jet; springmeans normally tending to raise the choke tube; a rotary throttle valve;means for rotating the throttle valve in one direction; a spring forrotating the said throttle valve in the reverse direction; a cam; meansfor giving a limited rotary movement to the cam when the throttle valveis moved beyond predetermined limits; and a bell crank lever engagingsaid cam and choke tube and serving to depress the choke tube when thecam moves in one 15 direction and to permit it to rise under theinfluence of the aforementioned spring when the cam moves in theopposite direction.

In testimony whereof I affix my signature in presence of two witnesses.

JOHN THOMAS J EN N INGS. Witnesses:

HAROLD J. L. Fonnnsrnn, MARY J. PAnKEs.

